There have been known an electric motor which converts electrical energy to rotational movement energy, a generator which converts rotational movement energy to electrical energy, and an electric device which functions as both an electric motor and a generator. These electric devices will be hereinafter referred to as rotating electric machines.
A rotating electric machine has two members which are located on the same axis and rotate with respect to each other. Normally, one member is fixed, while the other member rotates. By locating a coil on the fixed member (stator) and supplying electrical power to this coil, a rotating magnetic field is formed. The other member (rotor) rotates by interaction with this rotating magnetic field. The coil located on the stator is formed, for example, by attaching coil wires formed to have a predetermined shape to the stator and then connecting these coil wires to each other.
The below-listed Patent Document 1 discloses a technique of arranging a plurality of coils along the circumferential direction of a stator and connecting coil wires forming each coil via a bus bar. The plurality of bus bars are contained in a groove formed in a rail member, thereby forming a module.